/*
 * function a() {}
 * var a = 10
 * console.log(typeof a)
 */

/*
 * function func1() {}
 * function func2() {}
 * func1.prototype = func2.prototype = {}
 * const son = new func1()
 * console.log(son instanceof func1, son instanceof func2)
 */
function reverseNum(num) {
  const str = num + ''
  console.log(str.split('').reverse().join(''))
}
reverseNum(123)